I was put to sleep and was getting laughing gas right before my dental surgery. The doctor started naming my gums and then they said that I started coughing uncontrollably and they could not get me to stop. They also said that my oxygen level dropped and they had to put put a full oxygen mask on my face to get my oxygen levels back up until they could get me woken up from the anesthesia. They use anesthesia to put me to sleep and also gave me laughing gas.When I woke up I did not know where I was at or what was going on. My husband has a video of me after I first woke up and my eyes were bloodshot and apparently I was coughing so hard I had makeup running down my face. The dentist said I have a sinus infection but I was at my doctor two days before this and I was fine. What could have caused this? I'm very concerned.